Hi @Jose-Mejia, We are designing an audio expansion to go with the Omega. For now there isn't a way to play audio with the Omega. However, you can try getting an USB audio adapter. There should be a driver for it made for OpenWRT.

Hmmmm. I was going to say that you could do a PWM signal and a small filter. I tried googling for audio from an Adruino and there are examples that go in that direction, but that requires an onboard hardware timer. I think I remember seeing that on the Omega to control servo's (PWM) you need to do it in software (count milliseconds) or in hardware like the motor shield. Is that right? @Boken-Lin

@Chris-Ward I was going to suggest using PWM - there is code in fast-gpio for generating PWM output and I am working on alternative C/C++ code for accessing GPIO that might make some of this more friendly. Writing in C/C++, the timer issues should not be a major problem - though an onboard hardware timer (with interrupt capability) would certainly make things a bit easier.

However, I suspect that the original poster wanted something a bit more sophisticated which would need a fair amount of processing to convert the mp3 to a sequence of (possibly multi-channel) GPIO output.
I would think that something with an A/D converter would be needed - it would be possible to wire up one of multiple available i2c based A/D chips but this might take quite a bit of work.